Copper-zinc-manganese alloy



Patented May 2, 1944" OFFICE COPPER-zlNC-MANGANESE ALLOY Cresap M. Moss,

to Chicago Develop Ill.

Salt Lake City, Utah, assignor ment Company, Chicago,

yo Drawing. Application Au ust 15, 1941, Serial No. 407,005.

'1 claim. (01. 75-455) This invention relates to certain new and useful alloys of copper, zinc and manganese having materially improved physical properties Carpenter and Robertson, in their well known text Metals, disclose that manganese increases the strength ofcopper-zinc alloys within the range of 40% to 45% zinc, balance copper, at the rate of 1400 pounds per square inch up to 1% of manganese. Furthermore, in such alloys containing up to 1% manganese, the elongation is increased by They further disclose that greater additions of manganese lower the elongation, th latter becoming equal to the original value at 2% manganese, and at 5% manganese the elongation is 5% less than the original value. The properties described by Carpenter and Bobertsonresult from the use of conventional alumino-thermic manganese and silico-thermic manganese, which manganeses, as is well known, contain relatively substantial proportions of impurities in the form of iron, and oxides such as aluminum oxide or silicon oxide, and the like.

In accordance with the present invention, it has been discovered that it highly purified manganese is employed, namely, a manganese having a purity of at least 99.0% and especially at least 99.9%, which manganese is substantially free from iron, and is free from the oxides of aluminum and/or silicon, entirely diiierent properties result from the addition of such manganese to copper-zinc alloys of high purity. :Indeed, the alloys which are obtained in accordance with the strength is, generally, substantially uniformly increased by additions or up to of the high purity manganese.

While, in the example referred to hereinabove, the improvements in properties have been described in connection with sand cast alloys, the practice of the present invention yields similar marked improvements in such alloys in th cold rolled or the hot rolled forms. These results are brought about, as previously stated, by the utilization of manganese of an exceedingly high purpresent invention have entirely new and improved physical properties not heretofore known or obtainable in alloys of th general character involved.

In an illustrative example, an alloy was prepared by adding 8% or electrolytic manganese having a purity of 99.9% to an alloy containinl 45% zinc, balance substantially all copper, and- 'the' resulting alloy had substantially the same elongation as that of the original45% zinc-- 55% copper alloy. At the same time, the tensile strength of the alloy was materially increased. In sand cast alloys, the incorporation of 8% of electrolytic manganese into an alloy oi 45% nine, 55% copper, increases the tensile strength by 20,000 pounds per suture inch. The tensile ity so that neither iron nor oxides of aluminum and/or silicon ar incorporated into the alloy. For the successful practice of the'present invention, iron must not be present in the finished alloy in amounts greater than 0.05%.and the oxides of aluminum and/or silicon should be absent in any noticeable quantities.

While, as has been stated hereinabove, electrolytic manganese of at least 99.9% purity is particularly satisfactory for the practice of the present invention, other forms of highly pure manganese may also be utilized sflch as vacuum distilled manganese and the like. It is also highly desirable to em loy highly pure copper andzinc in the prepara on of the alloys, the electrolytic variety of these metals being especially satisfactory.

Those skilled in the art will readily understand the various uses to which th alloys 0! the present invention may be put in the light of the characteristics and properties which have been described hereinabove.

What I claim as new and desire to protect by Letters Patent oi the United States is:

An alloy 0! copper, zinc-andmanganese containing not'more than 0.05% iron and tree from the oxides of aluminum and silicon, said alloy containing about 45 zinc, about 8% manganese having a purity of at least 99%, balance substantially all copper, said alloy possessing an elongati n a least q al to that of an alloy of copper and zinc having the same zinc content but devoid of manganese and, in the sand cast form, an elongation of at least 20% in two inches. and a castiorm.

GREEN? H. M088! 

